MLA

Kissinger, Henry, 1923-2023. Morton, Louis. Box 42, folder 25. 1959-1962. https://collections.library.yale.edu/catalog/11783170.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 42, folder 25"])(1959-1962)[Morton, Louis]. https://collections.library.yale.edu/catalog/11783170.